Power-hacksaw.



R.G.BERRY. POWER HAoxsAw. APPIJGATION FILED MAB..13, 1912.

Patented Mar. 25, 1913.

UNITED STATES PATENT OFFICE.

. ROBERT C. BERRY,*0F INDIANAPOLIS, INDTANA.

POWERJ-IA'CKSAW.

To all whom t may concern Be it known that I, ROBERT C. BERRY,

a citizen of the United States, residing at. Indianapolis, in the county of Marion and State of Indiana, have invented a new and useful Power-Hacksaw, of .which the folloW-. ing is ahspecification.

It is thegobject of my invention to prevent `the wearing of the saw teethof a machine lvertical position of the saw at the time the lifting action is be n. This connectingV means comprises a ash-pot which allows free movement of the fluid within it in one direction only 4from one side of the piston to the other.

The'various novel" features of my invention will appear from the description andO drawi s', and will be particularly pointed out in t e'clai'ms.v

In the drawing, Figure 1 is an elevation of one form of machine back-saw embodying my invention, Fig. 2 a longitudinal section through the dash-pot; `Fig. 3 a sectionai view of the dash-pot piston a; 1 associated parts; Fig. 4. a .section on the line 4-4 of Fig. 3, but with the valve locked open; and Fig. 5 is a side elevation of the parts shown in Fig. 3.

4-Mounted onl a shaft 9 in the main frame 10 is a'saw guide 11, on which is slirably mounted a saw frame 12 provided with a vhack-saw blade 13, shown as about to begin to cut thebar 14. The -saw frame 12 1s reciprocated in any suitable manner, as in the manner 'covered by my Patent No. 907,445, from a crank pin 15 on a driving shaft v16.

A cam 20 isfixed on the driving shaft 16, and coperates with a roller 2,1 on one end of a lever 2v2 pi'voted at 23 yon the main frame 10. A dash-pot casing 24 is pivoted to the end of the lever 22 opposite the roller 21,*the piston rod 25 of this dash-pot being suitably connected to the saw guide 11, as by being pivoted to an arm 26 fixed to the shaft 9 carrying"v said saw guide. The lower end 0f the piste rod 25 is suitably attached Specification of Letters Patent.

f Application filed. March 13, 1912.

saw is Serial No. 683,577.r

to the piston 27, as by being screw-threaded. into nut 28 integrally connected with the piston 2T by four arms 29. The piston 2i", which is provided with a flexible piston. ring or packing 30 in the usual manner, l-s perforated centrally to receive the stem 31 of a valve 32, such valve being suspended at a slight distance below the piston 27 by pin 33 extending through the valve stem above said piston. 4The cooperating faces of the valve 32 and the piston 27 vare ranged to lit nicely when the valveis raised.

ln operation, the cam 20 forces the rolle.l 21 downward and the dash-pot casing upward at the completion of the forward or cutting stroke of the saw 13. This 'upward movement closes the valve 32'after a "very small but always uniform movement, depending upon the distance allowed'between the valve 32 and its seat; and the continued upward movement of thecasing 24 causes the piston 27 to move with it, thus tilting; the arm 2,6, and therefore the saw guide 1 to liftthe saw blade 13 slightly. The saw blade 13 remains lifted during its backward movement, at the completion of which the cam 20 allows the roller 21 to rise, under the influence of the spring v34, and the parts which before were:vv ifted, to fall. The valve 32 now opens, and remains open during thel cutting stroke, allowing the saw blade 13 and its supporting parts to descend slowly as the saw deepens the cut.

In order to allow the ready vertical adp liustment of the saw frame' 12 and the Saw guide 11, 'as for the purposes of changing the saw or the work, means is provided for holding the valve 32 in open position. This means preferably comprises a metallic plais 35 sleeved `on the piston rod 25 and having; two fingers 35 extending downward, be tween the arms 29 which prevent the finger#J from turning, toward the two ends of pin 33. This plate is spring pressed upward by a coil spring 37 above the nut 28. A tube 38 bear@4 on the upper side of the plate 35, and is provided at its upper end with a collar 39 an? handle 40 whereby it may be turned. The upper surface of the collar 39 is notched and coperates with a cross-pin 41 in the pist-on rod 25. By turning the handle 40, the sides of the notches the collar 39 act as cams and force the tube 38, the plate 35, and the fingers 36 downward against the action of the spring 37 to bring thettingers 36 into engagement with Patented Mar;'25,1913..

the ends .of the pin 33,-thus locking the valve 32 opens This permits any desired relative however, lfor the upward movement -Q'f the saw 'frame 1L, itis not necessary to hold' the.valve;32open, as thepressurev of the fiuid withinfthe dash-pot willdo that. If

- f it- 'isf-desiredv to lhold the parts in a raised position, the handle is put in normal position toJallow the valve 32 to close by the downward-pressure of the lifted.v parts on thefpisiton 27. -By forcing the valve open, by the :proper movement of the handle 40, theframejllfmay be returned to. operating position. i

WhatI claim as new is:

`A machine saw, comprising aA reciprocable saw frame, driving means comprising 'means for 4reciprocating said saw frame, and amechanical Aconnection between the driving means 'and saidfsaw frame for raising the latter i'nits return movement, said connecvtion comprisinga dash-pot.

-2.' Armachine saw,` comprising a pivoted -saW fgluide,a saw framereciprocable on said guide, "driving means comprising "means for reci'proc-ati'ng said saw frame onwsaid saw guide, and a connection between -said drivingmeans and said saw guide for tilting the 'latter Ato lift the saw frame during the return movement thereof, said-means comprising -acam and a dash-pot, one. member ofv which dash-pot is mechanically connectedtosaid saw guide and. the other tothe reciprocating means.

3. .Armachine saw, comprisingia pivoted saw guide, a saw frame reciprocable on said guide, driving means comprising means for 'reciprocating vsaid saw' frame on said sawV guide, fand aconnection between said driving means and'said saw guide for tilting the "latter to'lift the saw framedurfingthe re- 'turn movement thereof, said means comprisinga cam and a dash-pot, one member of which dash-pot is mechanically connected to said saw guide. and the other to' the reciprocating-means, said dash-pot being provided v with a valve vwhich closes when the action ofv the .cam mtends to move the two dash-pot members" relatively to eachother in the direction to lift the saw frame. i

4i. A machine saw, comprising a pivoted lsaw guide, a 'saw frame reciprocable on said guide, driving means comprising means for reciprocatmg said saw frame on said saw guide, a connectlon between said driving "meals and. said saw guide for tilting the latter to lift the saw frame during the retuilii movement thereof, said means compris'ing a cam and a dash-pot, one member of which dash-pot is mechanically connected .to said saw guide and the other tothe reciprocating means, said dash-pot being pro- `vided with a valve which closes when the action of the cam tends tomove the Vtwo dash-pot members relatively to each. other in the direction to lift the saw frame,"and manually operated means for opening said valve.

5. A machine saw, comprising a pivoted saw guide, a saw frame reciprocable on said guide, driving means comprising means lfor reciprocating said saw frame on said saw guide, a connection between said driving means and said saw. guide for tilting "the lat-ter to lift the saw frame during the return movement thereof, Said means compris- Ving acam and a dash-pot-,onevmember of which dash-potis mechanically connected tosaid sawc guide and the other to the ref ciprocating means, said dashfpot being pr'ovided with az valve which closes when the Vaction of the -caxn tends; to lmove thet'wo dash-pot members relatively toeach other in the direction to liftthe saw frame,- and manually operated means for locking said valve open. 1

6. In apower hack-saw, thecombination with the saw-carrying` member andv the power train for operating it, of a dash-pot comprising two cooperating members one containing a liquid and the other formin a piston submerged inv said liquid, a valve or limiting flow of liquid in one direct-ioma con'- nection bet-Ween one of the vdash-pot members and the saw-carrying member, aV-sup`v port for the other dash-pot member m0vable in the line ofthe dash-pot, and means operated by the power 'train for the hac-ksaw for reciprocating said support, forlthe 

